Scientists are developing a device to automate the process of in-vitro fertilisation.

They believe the technology may eventually be able to test embryos for genetic flaws.

Researchers David Beebe, of the University of Wisconsin, Madison, and Matthew Wheeler, of the University of Illinois at Urbana-Champaign, expect their work initially to be used for livestock production.

However, their eventual aim is to use for it human embryos.

New Scientist magazine reports that so far they have built prototypes that can carry out all the major steps involved in IVF, though not all on the same chip.

Conventional IVF involves several separate stages.

First, sperm and eggs are mixed together in a Petri dish.

Then once eggs are fertilised, they are transferred from dish to dish as they require different nutrients at various stages of development.

Mimics conditions

Conventional IVF may become outdated

The researchers have designed a device that mimics conditions inside a female reproductive tract.

It resembles a small glass slide and contains a network of tiny channels which are connected to programmable syringe pumps, which can move embryos around and add or remove fluids.

In tests, 75% of mouse embryos were cultivated to point where they were ready to be implanted into a female mouse - a much better success rate than that achieved by conventional IVF methods.

The researchers also successfully used the device to carry out a process known as "assisted hatching" in which the shell that encases early embryos is removed to encourage implantation.

The device allows many embryos to be cultured at once, and allows each one to be individually manipulated, potentially making it easier to weed out those of poor-quality.

Eventually, it should also make pre-implantation genetic diagnosis easier.

Normal practice

Dr George Seidel, a reproductive physiologist at Colorado State University in Fort Collins, said the work could represent the first step to IVF becoming the norm.

He said: "Fifty or 100 years from now, our in vitro procedures for parts or even all of pregnancy may end up being safer than dealing with the various things that occur in the body - in terms of viruses that the mother comes across, toxins, and so on."

But Tom Shakespeare of the Policy, Ethics and Life Sciences Research Institute in Newcastle, warned that use of the device could raise difficult ethical issues.

He said: "If we are talking about maximising the chances of becoming pregnant and carrying to term, then there's less argument.

"But if we are talking about either reducing genetic diversity or indeed enhancing selection then there are major questions."